Greenhouse gas emissions

Greenhouse gas emissions

Greenhouse gases

Water vapour is the most common greenhouse gas. However, three other greenhouse gases contribute to human-induced climate change:

Carbon dioxide (CO2) is released into the atmosphere by plants and animals. However, human activities, like burning fossil fuels, are increasing atmospheric concentrations beyond natural limits. CO2 is the main contributor to climate change, and accounts for about two thirds of greenhouse gases produced by human activities. Photosynthesis in plants removes CO2 from the atmosphere.

Methane (CH4) is not as abundant as CO2, but is 21 times more effective at trapping heat. It is released when vegetation decomposes in oxygen-free environments (such as a fire or landfill), as well as from animal digestive processes.

Nitrous oxide (N2O) occurs naturally in the environment, but human activities increase its atmospheric concentrations. This gas is most often released when chemical fertilisers and manure are used in agriculture.

For purposes of measurement, all greenhouse gases are converted to a common unit, called CO2 equivalent (CO2e)

Apart from water vapour, there are six main greenhouse gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride.

Many greenhouse gases (such as carbon dioxide, methane, water vapour, and nitrous oxide) occur naturally in the atmosphere, while others are human-made (synthetic).

Synthetic greenhouse gases, used in industry or created as a by-product of industrial processes, include chlorofluorocarbons, hydrofluorocarbons, and perfluorocarbons, as well as sulfur hexafluoride.

Increases of the main greenhouse gas, carbon dioxide (CO2), primarily results from burning petrol, coal, oil, and natural gas (in cars, industry, and electricity generation), and from certain land-use activities (such as clearing trees and ploughing the soil). While many sources release carbon dioxide, there are also 'sinks' of carbon dioxide - that absorb greenhouse gases from the atmosphere. For example, plants remove carbon dioxide from the air during photosynthesis, and oceans absorb carbon dioxide.

Victoria's greenhouse profile

Of the greenhouse gases emitted in Victoria, carbon dioxide is the most significant, though methane emitted from livestock and agricultural activities also make a significant contribution.

In 2007, Victoria's total net greenhouse gas emissions were 119.17 million tonnes of CO2-e. Victoria's total emissions are higher than some nations, including other industrialised countries with significantly larger populations, such as Austria, Hungary, Portugal, Slovakia, Sweden and Switzerland.

Victoria's high emissions totals result from our reliance on brown coal, a greenhouse gas intensive fuel, for electricity production. Over ninety per cent of Victoria's electricity is produced from brown coal. Together, Victoria's power stations produced 53% of the state's total greenhouse gas emissions in 2007.

Victorian greenhouse gas inventory

Greenhouse gas inventories present data on emissions of a range of greenhouse gases, and on the removal of these gases from the atmosphere by 'sinks'. The emissions and removals recorded in these inventories relate to human activity. The data is categorised by sector, and presented for different kinds of industry and activity.

The 2007 inventory is the most up-to-date information on Victoria's greenhouse gas emissions available. The data presented in this document are derived from the National Greenhouse Gas Inventory, which has been prepared by the Commonwealth Department of Climate Change, in a format consistent with international guidelines. This inventory supersedes all previous Victorian inventories.

The information identifies Victoria’s contribution to national greenhouse gas emissions, and reveals the relative contribution of different sectors to total emissions, along with trends over time.

The Victorian Greenhouse Gas Inventory 2007 presents a summary of the level and trends in greenhouse gas emissions sources and sinks in the state of Victoria for the years 1990-2007.

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VGGI 2007 (PDF - 127 KB)

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